The actor said that on the historic night he was surprised at his hotel by model Edie Sedgwick who turned up wearing a rain coat with nothing underneath.
Midway through having sex they heard a voice say on the TV: "One small step for a man. One giant leap for mankind" as Neil Armstrong walked on the Moon.
Beatty also claimed that Noel Coward also once tried to seduce him by saying that homosexuality was "marvelous".
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Biographers have claimed that Beatty slept with 12,775 women during his career, a figure which he has denied.
But he has had a long string of lovers, reportedly including Madonna, Julie Christie, Barbara Streisand, Cher and Joan Collins.
Speaking to Vanity Fair, Beatty, 79, denied that he had bedded Jacqueline Kennedy, Bianca Jagger and Mia Farrow.
However he said that he did sleep with Sedgwick, an 'It' girl who was a muse for artist Andy Warhol.
The moment had passed, and the two just stared at the television for the rest of the night
Beatty said that it happened when he was staying at the Delmonico Hotel in New York and there was a phone call from the lobby.
It was Sedgwick who had met the night before at a nightclub.
They had only chatted briefly so he was surprised when she turned up the next night at his room wearing just a yellow raincoat.
Vanity Fair reported: "The television was on. And taken by surprise, he wasn't all that sure he could rise to the occasion.
"But she was insistent, flirting and nuzzling. Eventually he gave in, and as they fell to the floor, they suddenly heard on the television: 'One small step for a man. One giant leap for mankind'.
"The moment had passed, and the two just stared at the television for the rest of the night'.
Vanity Fair also reported on how Coward tried to seduce Beatty whilst he in London when they had tea at the Savoy.
Coward reportedly asked him: "Dear boy, have you ever tried homosexuality?"
Beatty was said to have replied: "No. I have my hands full at the moment."
Coward is then said to have responded: "You really should, you know. It's marvellous."
In the interview Beatty also spoke of the time he met Marilyn Monroe at a house in Malibu owned by actor Peter Lawford.